Semiconductor Plasma Etching With Cyclic Passivation for High Aspect Ratios
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Solution Overview
Problem
The increasing aspect ratios and decreasing line widths in semiconductor devices complicate the semiconductor manufacturing process, making it challenging to form high-aspect-ratio structures with high reliability.
Innovation Solution
A method involving alternating and iterative flow rate ratios of oxygen and carbon-fluorine process gases in a plasma etching process, with constant source and bias power, to etch and passivate the etch target layer, ensuring consistent flow rates and improved plasma control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional etching processes are used with increasing aspect ratios and decreasing line widths, then semiconductor device integration is improved, but manufacturing reliability deteriorates due to process difficulty
Solution Approach 1:
The patent applies periodic action by alternately switching between etching process conditions and passivation process conditions in a cyclic manner. The etching condition (first process gas with oxygen and carbon-fluorine at first flow rate ratio) and passivation condition (same gases at second flow rate ratio) are periodically applied to enable controlled etching of high aspect ratio structures while preventing defects, thereby maintaining manufacturing reliability during high integration processes
Solution Approach 2:
The patent utilizes parameter changes by dynamically adjusting the flow rate ratios of process gases between etching and passivation phases, while maintaining constant source power and bias power. This parameter control allows precise management of plasma chemistry to achieve both high etching efficiency for integrated structures and defect prevention for manufacturing reliability
2Manufacturing precision
If plasma etching is performed to etch the etch target layer, then material removal is achieved, but defects such as bowing and non-open defects occur
Solution Approach 1:
The patent implements periodic alternation between etching mode (first flow rate ratio of oxygen and carbon-fluorine gases) and passivation mode (second flow rate ratio of same gases). This periodic switching enables complete removal of etch target layer material while periodically passivating surfaces to prevent bowing and non-open defects, thereby achieving both precision and defect-free etching
Solution Approach 2:
The patent converts the potentially harmful effect of excessive etching (which causes bowing and non-open defects) into a beneficial process by introducing periodic passivation steps. The passivation phase, using the same carbon-fluorine containing gases, deposits protective layers that prevent defect formation, transforming what would be harmful over-etching into a controlled, defect-preventing process
3Manufacturing precision
If process gases are provided at varying flow rates to etch and passivate, then etching and passivation are achieved, but plasma stability deteriorates
Solution Approach 1:
The patent applies parameter changes by controlling flow rate ratios of process gases while maintaining constant source power and bias power parameters. This selective parameter control allows variation in gas composition for etching versus passivation while keeping plasma generation conditions stable, achieving both process control and plasma stability
Solution Approach 2:
The patent implements preliminary action by pre-establishing constant source power and bias power conditions before initiating the alternating etching and passivation cycles. This preliminary stabilization of plasma generation parameters ensures that subsequent flow rate ratio adjustments for etching and passivation do not disrupt plasma stability
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enhances the reliability of semiconductor device manufacturing by stabilizing the plasma environment and preventing defects such as bowing and non-open defects, thereby improving the precision and effectiveness of the etching process.
Implementation Method 1
source power for generating plasma based on the first and second process gases
Implementation Method 2
etching an etch target layer by providing a first process gas including oxygen and a second process gas including carbon and fluorine
Implementation Method 3
bias power for accelerating the plasma
Implementation Method 4
providing the first process gas and the second process gas to the process chamber at a second flow rate ratio to passivate the etch target layer
Data Source
AI summary
A method of manufacturing a semiconductor device includes: providing a first process gas including oxygen and a second process gas including carbon and fluorine to a process chamber at a first flow rate ratio to etch an etch target layer; and providing the first process gas and the second process gas to the process chamber at a second flow rate ratio to passivate the etch target layer, wherein a flow rate of the first process gas is substantially constant.